Electromagnetic chuck



Oct. 3o, 192s. 1,689,616"

J. BING ELECTROMAGNETI C CHUCK Filed June 3, 1924 I '57h-fum? v enteringPatented Ot. 30, 1928.

UNITED isri.

JULIUS BING, 0F EISENAGH,

EISENACH, GERMANY.

TES PATENT OFFICE.

GERMANY, ASSIGNOR TQ MAGNET-WERK M. '.B. IBI. SPEZIALFABRIK FURELEKTROMAGNET-APPARATE, OF, EISENACH,

ELECTROMAGNETIC CHUCK.

Application led June 3, 1924, Serial No. 717,657, and in Germany June 5,1923.

This invention hasreference to means of producing a tight andwater-proof packing for electromagnetic chucks or work holding apparatusby means of which moisture is excluded from'coming in contact with themagnetizing coils of said devices` In the electromagnetic chucksheretofore in use it has been found to be practically impossible to somount the coil or coils in the apparatus as to protect them frommoisture. 'Ihe man'- -ner of imbedding the coils usually employed 'bycasting a resinoustor similar compoun 'around them, while being suicientto prevent the entrancel of the 'particles of water which are liable tond their way through the crevices and joints of the magnet casing forsome time, does not .constitute a permanent protection, inasmuch as thecompound loses its plasticity by the frequent heating, there producingcapillary crevices through which the water iinds an easy entrance andcauses short-circuiting and eartliing.`

In accordance with this invention the difficulties referred to areavoided by employing oil as an insulating agent. Inasmuch as the wateris heavier than oil it will descend and collect at the bottom of thecontainer. In order'to prevent its coming in contact with the coil orspool, means are provided to mount the spool in a box with open topdisposed in the winding chamber of the apparatus, the said box beingclosed by a suitable cover, preferably provided with an upwardlytapering, laterally outwardly extending roof shaped portion.

The invention in a preferred form of construction, embodying anexempliication of the principles of the invention,l `is shown on theaccompanying drawing in a some-l what conventional manner in sectionalview through the chuck.

In the drawing a is the shell or casing forming the magnet body of theapparatus .which is provided with .the usual annular winding chambersurrounding the core i of the mag'- net. In this chamber Z) a ringshaped box o of sheet metal or the like and in the construction shown byway of. example, with open top is provided in which the energizing spoolor coil d is mounted 1n any. suitable manner. The cover e for closingvth1s box is roofshaped, and possesses outwardly protruding edges 7. kis the top or. work holding plate which in the usual way-1s formed f ofthe y upper portion of the casing, and these two openings g and h may beused for the purpose of causing a current of cooling agent, water or thelike to flow through the casing.

'l`he invention has been shown and. described in its broad aspects only,but it is obvious that it is not limited to they particularconstructionrepresented by way of exemphtication merely, but it is susceptible ofvarious moditicationsand forms of constructions according torequirements, and without deviating from the spirit of this invention asset forth in the appended claims.

The invention is not restricted to a particular number or shape ofwinding chambers, and more than one spool or coil may be provided in theapparatus.

a base of magnetic material provided with an annular channel extendingdownwardly from its top, aI cover plate of magnetic material coveringthe channel, an annular open topped casing seated in said channel andspaced from the sides and bottom of said channel, a removable annularcover having inner and outer peripheral flanges and of inverted V- shapebetween said iianges, said -cover rest- .ing on the open top of thecasing with the flanges extending down the sides thereof, and a magnetwinding in said casingand hav ing its convolutions extendinghorizontally through said casing.

2. An electro-magnetic chuck comprising 4a base of magnetic materialprovided with -an annular channel extending downwardly from its top, acover plate of magnetic material covering the channel, an annular opentopped casing seated in said channel and spaced from the sides andbottom of said channel, a removable annular cover having inner and outerperipheral flanges and of incasing walls and the space between theCasverted V-shape between said langes,said cover ing and channel walls,said base having nor- 10 resting on the open -top of the casing withmally closed inlet and drain ports 'communithe'iianges extending downthe sides thereeating with the upper and lower parts of 5 of, a magnetwinding in said easing and haN- the channel respectively.

ing its convolutions extending horizontally In testimony whereof I alixmy signature. through said casing, and an insulating oil I' filling thespace between the winding and J ULIUS BING.

